Probing miniband structure and Hofstadter butterfly in gated graphene superlattices via magnetotransport

Alina Mreńca-Kolasińska, Szu Chao Chen, Ming Hao Liu

研究成果: Article同行評審

摘要

The presence of periodic modulation in graphene leads to a reconstruction of the band structure and formation of minibands. In an external uniform magnetic field, a fractal energy spectrum called Hofstadter butterfly is formed. Particularly interesting in this regard are superlattices with tunable modulation strength, such as electrostatically induced ones in graphene. We perform quantum transport modeling in gate-induced square two-dimensional superlattice in graphene and investigate the relation to the details of the band structure. At low magnetic field the dynamics of carriers reflects the semi-classical orbits which depend on the mini band structure. We theoretically model transverse magnetic focusing, a ballistic transport technique by means of which we investigate the minibands, their extent and carrier type. We find a good agreement between the focusing spectra and the mini band structures obtained from the continuum model, proving usefulness of this technique. At high magnetic field the calculated four-probe resistance fit the Hofstadter butterfly spectrum obtained for our superlattice. Our quantum transport modeling provides an insight into the mini band structures, and can be applied to other superlattice geometries.

原文English
文章編號64
期刊npj 2D Materials and Applications
7
發行號1
DOIs
出版狀態Published - 2023 12月

All Science Journal Classification (ASJC) codes

  • 一般化學
  • 一般材料科學
  • 凝聚態物理學
  • 材料力學
  • 機械工業

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